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301 Uppsatser om Fish farming - Sida 2 av 21
The economic consequences of Striga hermonthica in maize production in Western Kenya
Kenya is a country of 35 million people and is situated in Eastern Africa. 70% of thepopulation works within the agricultural sector and for many of them food insecurity is amajor problem. Maize and beans are today the staple food for many households. Goodfarming conditions enable two harvests per year and a potential maize yield of 4-5 tons perhectare.A major problem for many farmers in this area is the increase of the weed striga. The weedcauses severe yield losses, and has a major economic impact on smallholders.
Småskalig vattenkraft vid Olofsfors bruksmuseum : Med faunapassage
In Sweden there are 1894 small-scale hydropower plants in operation, which together generate 4.3 TWh of electricity per year according to Swedish hydropower compound (SVKF, 2011). This corresponds to the annual consumption of about 860,000 Swedish households (based on an annual consumption of 5000 kWh). In the mid-1950s there were around 4000 small-scale hydropower plants in operation in Sweden before cheap fossil fuels and uranium competed with them, in the current situation only 1,894 of these are in use. If slumbering small hydropower plants once again would be taken into use and some new ones are built, we would be able to extract about 7 TWh of renewable electricity from these annually in Sweden, representing about 1.4 million households.The thesis intends to calculate and construct a hydroelectric power plant at the existing dam in Olofsfors and give suggestions on how the power station should run during the time that fish migration is greatest in Leduån.The turbine and generator to the station in Leduån at Olofsfors is designed by the height of the fall and the water flow through the dam. The turbine selected for the station is a CK-1000RM turbine with a 4-pole 250 kW generator from Cargo & power turbine Sweden AB, which is expected to deliver 1.2 GWh per year.
Fisksamhället i Spexhultasjön, Nässjö
The lake Spexhultasjön is a moderate humic mesotrophic lake that is not acidified. The fish fauna was investigated by using a standard method for sampling freshwater fish with multi mesh gill nets. The fish fauna was diverse with perch, pike, tench, common whitefish, and roach. Perch and roach dominated. There were few pikes.
Fiskevård och delning av fiske vid lantmäteriförrättningar : Studie av FBL 3 kap 8 §
AbstractThis bachelor thesis was performed at the Royal Institute of Technology in Stockholm on behalf of the Land Survey Authority. The thesis is about fish conservation and division of fishing water at official duty. It is the Land Survey Authority that examines division of fisheries, but before a case can be implemented, certain requirements must be achieved such as FBL 3:8, which prevent divisions that are deleterious for fish conservation. The purpose of this thesis is: to obtain a clearer view how FBL 3:8 should be applied in practice, how the application differs between the offices in central Sweden, and how fish care is regulated at both international and national levels.At an international level, in EU the commercial fishery is regulated through the common fisheries policy (CFP). The fisheries policy consists of a reform that will last for 10 years.
Something fishy in Christians : Dietrekonstruktioner genom analys av stabila isotoper på tidigmedeltida skelett från Rambodal, Styrstad Sn, Östergötland
Dietary patterns has varied throughout history, both due to resource and cultural limitations. In this thesis, a study was conducted to establish the dietary patterns of eight individuals from an early Midieaval gravesite in Rambodal, Östergötland, in order to explain why they were buried there. This was done through stable isotope analysis on collagen extracted from bone and tooth on the buried individuals. The analysis showed that these indviduals had a diet that was mainly based on freshwater fish. This suggests that these people may have been christians, due to the fact that fish was not regarded as meat and therefore you did not have to abstain from it during periods of fasting.
Pre-spawning habitat selection of subarctic brown trout (Salmo trutta L.) in the river Vindelälven, Sweden
Habitat selection of migratory brown trout at the upper reaches of River Vindelälven, wasstudied in September during the pre-spawning period. The fish migrate from down- orupriver lakes for spawning in the river and data was collected by habitat mapping andradio-telemetry. Habitat selection of fish was analysed with preference curves andstatistical modelling, using the physical variables; depth, stream velocity and streambedsubstrate. Preference curves were derived by comparing fish habitat use with their nearbyavailable environment while the statistical modelling aimed to answer three main questions.1) Do the trout have a specific preference of depth, water velocity and streambed substrate?2) Is there any difference in habitat selection between sexes? 3) Is there a shift in habitatselection over time? The preference curves indicated that trout favored water depths of 1-2m, velocity compositions characterized as glides (c.
Barriers to convert to organic farming and the role of risk : an empirical application on Swedish data
To understand the motives, and perhaps more importantly the barriers, for farmers to convert from conventional to organic farming is of great interest for policy makers as well as for academics. In Sweden and in other EU countries, proposed targets of the area in organic farmland have failed to be reached in spite of different kinds of policy measures. Most studies agree that the average profitability seems to be comparable to or better in organic than in conventional farming. This would indicate that there must be other factors of importance which can explain the low particiapation rate. A higher perceived risk in organic farming with respect to yield and price is frequently brought up as a potential explanation within a qualitative framework.
Vandring av vårlekande fisk och jämförelse av fångst mellan ryssja och strömöversiktsnät i Hammerstaån, Stockholms län
During the last two hundred years many wetlands and streams in Sweden have been lowered to provide land for agriculture and forestry. Some of the coastal wetlands and streams probably served as spawning sites for certain species of fish in the Baltic Sea, but the present situation is not well known. As standardized methods to monitor fish in running waters are carried out during late summer or autumn, there is a need for methods to sample spring-spawning fish in these streams.The aim of this study was to survey the lower kilometer stretch of Hammerstaån in Stockholm, to investigate the extent to which the stream is used by spring-spawning fish. Furthermore, the study aims to evaluate a new type of survey fishing gill net called strömöversiktsnät (SÖN). This was done by comparing the catch of fish by SÖN with that of fyke nets.
Konsumentbeteende vid köp av färsk fisk : en kvalitativ studie för utveckling av ett produktkoncept hos ICA
Health and convenience trends dominate the food industry and retailing business of today.
The health consciousness is spreading while appealing product attributes concerning taste and
packaging also are increasingly important. At the same time, the competition is growing fierce
in the Swedish market with hard discount formats and niche concepts who also are trying to
provide the market with perishables. Therefore, the pressure to lower prices is increasing
making economies of scale and rationalization progressively more important.
In 2004, ICA launched private label meat packaged in a modified atmosphere. Consequently,
many stores went from in-store cutting-up and packaging to selling centrally packaged and
distributed meat. ICA is now developing a concept with fresh fish in modified atmosphere
packages and needs to increase the knowledge about the market and the consumer.
Förluster av nedströmsvandrande fisk vid turbinpassage : En fallstudie för att främja den småskaliga, såsom storskaliga vattenkraften
The expansion of the Swedish hydro power has contributed positively to the reduction of the environmental impacts from the fossil fueled power production. In the same time the extensive expansion has been proved to cause negative ecological and local environment impacts of a stream. This, in turn, has been affecting the biodiversity and fish stock negatively, which has been reduced. One of the underlying problems is the lack of possibility for the fish to pass the plants, but it is also directly correlated to the mortality rate of the fish passing through the turbine, which this study is investigating.The mortality rate has been computed for three different locations in Sweden, Untra, Tännfallet and a third one whose location is confidential, and is denoted as Case 1, 2 and 3. The model used to calculate the mortality rate in this investigation is based by existing blade strike models and knowledge and are investigating the death due to mechanical injuries from collision with a runner blade in the turbine.
What factors correlates with the use of game meat, wild fish, berries and mushroom in Swedish households : urban vs. rural areas
This study was made to see too what extent Swedes uses consumptive resources such as berries and mushrooms, game meat and meat from fish in their household on a yearly basis. I have also looked into the difference between rural and urban areas in Sweden. Further aim was to determine what factors that correlates with the participation in berry and mushroom picking and the use of game and fish meat within the household. The study was conducted in form of a mail survey that was sent to randomly chosen persons in every municipality in the six northern most counties in Sweden and in the county of Stockholm. In addition a sample was sent to randomly chosen persons on a national level.The results showed there is a difference in use between rural and urban areas in Sweden in all 4 investigated consumptive resources.
Hållbar vattenkraft i Nissan : En förstudie och konsekvensutredning över förutsättningarna för ökade vandringsmöjligheter med nya fiskvägar.
The hydropower from Nissan River is of national interest and produces annually 230 GWh from the twelve power stations in the main flow. For modified waters a consideration between the power production and the biological values has to be made. This reports serves as a pre-study for Nissans Vattenråd. It tries to evaluate some of the biological values in the Nissan basin and map the power production in the area. And the size and value of lost power production from new fishways for the twelve stations in the main flow.The investment of new fishways is calculated using simplified templates with values from the business.
Vandring av vårlekande fisk och jämförelse av fångst mellan ryssja och strömöversiktsnät i Hammerstaån, Stockholms län
During the last two hundred years many wetlands and streams in Sweden have been lowered to provide land for agriculture and forestry. Some of the coastal wetlands and streams probably served as spawning sites for certain species of fish in the Baltic Sea, but the present situation is not well known. As standardized methods to monitor fish in running waters are carried out during late summer or autumn, there is a need for methods to sample spring-spawning fish in these streams.The aim of this study was to survey the lower kilometer stretch of Hammerstaån in Stockholm, to investigate the extent to which the stream is used by spring-spawning fish. Furthermore, the study aims to evaluate a new type of survey fishing gill net calledströmöversiktsnät (SÖN). This was done by comparing the catch of fish by SÖN with that of fyke nets.
Utvärdering av rörelsemönster hos öring (Salmo trutta) utifrån otolitmikrokemi
The classic view of trout (Salmo trutta) life history is that trout begins its life in freshwater, migrates to the ocean after about 1-4 years and then returns to freshwater to spawn. As trout fry have been caught at the mouth of the River Emån, near the Baltic Sea, researchers have speculated that some trout emigrate during their first year of life. The purpose of this study was to describe the variation in the length of time trout reside in freshwater before they migrate to the ocean for the first time. Another purpose was to investigate whether it was possible to discern where and how long the fish spent in freshwater and saltwater during different parts of their lives. Between 2007 and 2009, 23 adult trout were captured in the River Emån in southeastern Sweden.
Gäddan & fisket i Ringsjöholm : en osteologisk metodstudie i säsong & bevarande
This paper presents the results from an osteological method study of the Ringsjöholm fishbone material. Ringsjöholm is located in Scania, southern Sweden and is 14C dated to 5960-5200 B.P. The aim of this paper is to critically analyse methods used on fish bone material in estimations of season. Three different approaches were used to estimate the fishing season at the Ringsjöholm settlement; 1) identified species, 2) size estimations of the pike based on Enghoffs (1994-95) regression formulae of os dentale, and 3) growth rings of the pike vertebrae.The identified species and the size estimations of the pike points to the fishing being active both during spring and summer. Growth rings analysis of the pike vertebrae didn?t give any quantitative results because of fragmentation.